Spray gun



Feb.

W. STANLEY SPRAY GUN Filed March 18", 1946 Arm/MEV Patented Feb. 6, 1951 UNITED STATES PATENT OFFICE SPRAY GUN William Stanley, Chicago, Ill.

Application March 18, 1946, Serial No. 655,050

3 Claims. 1

The invention relates to spray guns.

One object of the invention is to provide an improved spray gun which functions as a portable self-contained unit for operating a reciprocating piston for discharging iiuid carrying the material to be sprayed through a nozzle.

Another object of the invention is to provide a self-contained spray gun including an electric motor and a reciprocating pumping mechanism which is eiiicient in operation and simple in construction.

Other objects of the invention will appear from the detailed description.

The invention consists in the several features hereinafter set forth and more particularly dened by claims at the conclusion hereof.

In the drawings:

Fig. 1 is a vertical section or a spray gun ernbodying the invention, parts being shown in ele- Vation.

Figs. 2 and 3 are plan views of the rotary cam which imparts compression strokes to the piston, viewed from different angles.

Fig. 4 is a face view of said cam.

Fig. 5 is a face view of the piston.

Fig. 6 is a section of the piston.

Fig. 7 is an opposite face view of the piston.

The invention is exemplified in a unit comprising a cylindrical casing section or shell i which is closed at one end by a removable head 9. An electric motor l2 with a shaft E4 is housed in section 3 and head 9. A casing section is has one of its ends secured in casing section S and is provided with a cross-wall in which is mounted an anti-friction bearing il' for the motor-shaft I4. A pistol grip l5 is suitably secured to the casing sections l@ and for manipulating the unit. A self-opening switch iii is mounted in the grip i5, electrically connected to the motor E2 for controlling its operation, in manner well understood in the art, and includes a button i3, which can be easily pressed by the hand of the operator.

A rotary cam I8 is disposed in casing section lli and fixedly secured to the end of motor-shaft I4 and is adapted to impart rectilinear compression strokes in one direction to the piston hereinafter described.

A wall I9 is secured by screws in one end of the casing section lil. A cylinder 2t is formed coaxially with the motor-shaft i4 in a casing section 2i! and the inner end oi the cylinder-forming portion of said section is screw-threaded to the wall le which constitutes a head for one end of said cylinder. Casing section 23 is also provided with a depending flange 2| in which the upper end or neck of a receptacle 22 for the liquid to be sprayed is detachably secured in any suitable manner.

A discharge nozzle 28, -which is provided with a check-valve 29, is connected by a port 2'1 with cylinder 26. A branch port 3c has its upper end communicating with the port 2l inwardly of valve 2Q and communicates with a tube 3l which eX- tends to a point adjacent the bottom'of receptacle 22. Check-valve 2Q is adapted to close the discharge through nozzle 2S, during the suction stroke of the piston hereinafter described and to open for the outflow of fluid during compression strokes. A check valve 5d in port 3i)v is adapted to cut off flow of air to tube 3| during the compression strokes.

A piston which as slidably mounted in the cylinder 245 comprises a head 35, a plate Si and a packing ring 36 clamped upon head 35. The packing-ring 33 is cup-shaped and includes a peripheral liange 33 which engages the periphery of cylinder 25.

A pair of diametrically opposite stems lll are secured to the piston for operation in one direction by the rotary cam it. Stems it extend through and are slidably guided in cylinder head IQ. Each stem lid is provided with a shoulder 45 against which the piston head 35 seats, extends through openings in head 35, packing 36 and plate Si', and is riveted to clamp packing ring between head 35 and plate 3l. The rotary cam E8 is provided with cani surfaces on one of its faces which engages the stems lid for imparting compression strokes to piston 3A. Preferably the stems are provided with inclined end faces 5! for engaging the cam surfaces 48. A coil spring oi the compression type is interposed between the outer end wall cylinder 26 and the plate 3l of piston for imparting suction strokes to the piston and holding the ends 5i@ of the stems :ifi in contact with cam surfaces Alli. The rotary cam i3 is provided with cam surfaces on one of its faces which engage the stems 4d for imparting compression strokes to the piston. These cam surfaces have circumferentially and somewhat gradually inclined or helical surfaces "i9 and abrupt surfaces 59 between the high and low points of the portions is. The helical cam-surfaces is will impart relatively gradual compression strokes to the piston, and the abrupt surfaces 5c will permit more rapid suction strokes to be produced by spring 52.

The operation of the spray gun will be as follows: assuming the receptacle 22 to be loaded 3 with liquid to be sprayed, the operator will hold the entire unit from the grip I4 and manipulate the unit in whichever direction may be desired. The operator presses the button of switch It to close the circuit for the operation of motor l2; whereupon rotary cam I8 will be continuously and uni-directionally rotated as long as the switch is held closed. Outstrokes will be imparted to the piston by stems 49 and cam surfaces 48 against the force of spring E2. Spring 52 will impart alternate suction strokes to the piston and hold stems G4 engaged with the cam surfaces 49.

During the instrokes imparted to the piston by spring 52, check-valve 29 will close and fluid will be quickly drawn by the suction of the piston into the cylinder 26. During the out-stroke of the piston, the vapor in the' cylinder will be compressed and discharged in a direct-ed stream through nozzle 21 by compression of the iiuid in the cylinder. The compression stroll-,es will be relatively gradual While the suction strokes will be rapid. This relative variation in the speed of the piston causes the fluid to be effectively drawn into the cylinder and discharged in the form of a spray.

The invention exemplifies a portable spray gun unit of simple construction in which the pumppiston and cylinder are coaxial with the electric motor and the rotary cam is utilized for imparting pressure strokes to the piston and a spring is used for imparting suction strokes to the piston. The entire unit is compact so it can be easily handled and manipulated. The discharge of the vaporized liquid from the cylinder is effected directly from the cylinder through the nozzle. The invention is adapted ior spraying insecticides, paints and other liquids. The rotary cam operated directly from the motor-shaft for imparting compression strokes to the piston provides a simple high speed construction which is efiicient in spraying. The unit is also light in weight to facilitate its manipulation in directing the spray to the work.

The invention is not to be understood as limited to the details described, since these may be modiiied within the scope of the appended claims Without departing from the spirit and scope of the invention.

Having thus described the invention, what l claim as new and desire to secure by Letters Patent is:

l. A portable gun for spraying material from a receptacle through a nozzle, comprising: a casing, an electric motor mounted in the casing, a cylinder in the casing corninunicatively connected with the receptacle and the nozzle, a piston slidable in the cylinder for producing pressure therein, a motor-driven rotatable member coaxial with the piston and having a side face confronting the piston provided with a plurality of oppositely disposed cares having side faces for imparting axial thrust, a ed wall in the casing between the rotatable member and the piston and closing the inner end ci the cylinder, a plurality of oppositely disposed stems exiending through and slidable in said wall, each having one of its ends ixediy secured to 'the piston and its opposite end engaging and receiving direct thrust from the side faces o the cams for iinparting compression strokes to the piston, and a spring for slidably retracting the piston and urging the ends of the stems in engagement with the side faces of the cams.

2. A portable gun for spraying material from a receptacle through a nozzle, comprising: a casing, an electric motor mounted in the casing, a cylinder in the casing coaxial with the motor and communicatively connected with the receptacle and the nozzle, a piston slidable in the cylinder for producing pressure therein, a motor-driven rotatable member coaxial with the piston and having a side face confronting the piston provided with a plurality of oppositely disposed cams having side faces for imparting axial thrust, a xed cross-wall in the casing between the rotatable member and the piston and closing the inner end of the cylinder, a plurality of oppositely disposed stems extending through and slidable in said wall, each having one of its ends Xedly secured to the piston and to its opposite end engaging and receiving direct axial thrust from the side faces of the cams for imparting compression strokes to the piston, and a spring for slidably retracting the piston and urging the ends of the stems in engagement with the side faces of the cams.

3. A portable gun for spraying material from a receptacle through a nozzle comprising: a casing. an electric motor mounted in the casing, a cylinder in the casing comniunicatively connected with the receptacle and the nozzle, a piston slidable in the cylinder for producing pressure therein, a motor-driven rotatable member coaxial with the piston and having a side face confronting the piston provided with a plurality of oppositely disposed cams having side faces for imparting axial thrust, a xed cross-Wall in the casing between the rotatable member and the piston and closing the inner end of the cylinder, a plurality of oppositely disposed stems extending through and slidable in said wall, each having one of its ends xedly secured to the piston and to its opposite end engaging and receiving direct axial thrust from the side faces of the cams for imparting compression strokes to the piston, and a spring for slidably retracting the piston and urging the ends of the stems in engagement with the side faces of the cams, the casing comprising a section in which the cylinder is formed, and a separable section around the rotatable member, to both of which sections the cross-wail is detachably connected.

WILLIAM STANLEY.

REFERENCES CTED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 165,027 Riley June 29, 1875 236,747 Wood Jan. 18, 1881 480,968 Bullard Aug. 2, 1892 689,208 Masterson Dec. 17, 1901 1,783,940 Trumble Dec. 2, 1930 2,013,639 Steinhart et al Sept. 3, 1935 2,195,929 Klett Apr. 2, 1940 2,321,828 Lane June 15, 1943 

